1. Field of the Invention
The present invention relates to a clutch including damper springs which transmit, to a clutch outer, torque inputted to an input rotator. The clutch is provided in a power transmission device to which power of an internal combustion engine is transmitted, the power transmission device, for example, being mounted on a vehicle.
2. Description of Background Art
As a clutch including damper springs, for example, there is one disclosed in Japanese Patent Laid-Open No. Hei 5 (1993)-248512. In this clutch, a thrust washer is interposed between a clutch outer and a primary driven gear meshing with a primary drive gear fixedly mounted on a crankshaft of an internal combustion engine. Moreover, the thrust washer is disposed inward of a damper formed of a coil spring in a radial direction.
In the above-described conventional technology, a point of application of torque applied from the primary driven gear to damper springs (dampers) and a point of application of torque applied from the primary driven gear through the damper springs to the clutch outer are offset to each other in the direction of the shaft axis. Accordingly, when the torques are radically varied, a phenomenon (hereinafter, referred to as “tilting of clutch outer”) occurs that a rotation centerline of the clutch outer is deflected with respect to a rotation centerline of the primary driven gear. Then, a degree of the tilting of the clutch outer becomes larger as an amount of the above-described offset becomes larger.
The tilting of the clutch outer, which is as described above, is suppressed to some extent by the thrust washer of the above-described conventional technology. However, in order to further suppress the tilting of the clutch outer, it is necessary to increase the rigidity of a supported portion (for example, a boss portion engaged with the primary driven gear) in the clutch outer. In this case, a weight increase of the clutch is brought about.